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The development of massive open online courses (MOOCs) has proceeded through three generations, and in all three, online discussions have been considered a critical component. Although discussions in MOOCs have the potential to promote learning, instructors have faced challenges facilitating learners' knowledge inquiry, construction, and management through social interaction. In addition, understanding various aspects of learning calls for more mixed-method studies to provide both quantitative, generalized analysis and qualitative, detailed descriptions of learning. This study fills these practice and research gaps. We designed a Chinese MOOC with the support of a pedagogical strategy, a learning analytic tool, and a social learning environment in order to foster learner engagement in discussions. Mixed methods were used to explore learners' discussion patterns, perceptions, and preferences. Results indicated that learners demonstrated varied patterns, perceptions, and preferences, which implies a complex learning process due to the interplay of multiple factors. Based on the results, this research provided theoretical, pedagogical, and analytical implications for MOOC design, practice, and research.

The tribological properties of lubricants containing the same additives often vary with varying hardness and composition of the frictional parts. This means that, in terms of the effectiveness of lubricant additives, most of current researches using GCr15 steel to assemble the frictional pair could not be directly cited by the moving parts made of other materials. Aiming at verifying if RNS‐1A‐PIBSA (referring to amino‐functionalized silica nanoparticle [RNS‐1A] after secondary surface‐capping by polyisobutylene succinic anhydride [PIBSA]) is suitable for multiple frictional parts made of different materials with varying hardness and composition, herein we investigate its applicability an additive in poly‐alpha‐olefin 6 (PAO6) base oil to three types of sliding pairs constructed from GCr15 steel, #45 steel, and ductile iron with much different hardness and composition by SRV‐5. A series of analyses of worn surface morphology and composition demonstrate that, independent of the composition and hardness of the frictional pairs, RNS‐1A‐PIBSA added in PAO6 base oil can form silica deposition film on the rubbed surfaces of the three kinds of sliding pairs, thereby effectively reducing friction and wear. Besides, we also examine the effect of RNS‐1A‐PIBSA on the thermal stability of the PAO6 base oil, and found the nano‐additive RNS‐1A‐PIBSA can delay the thermal decomposition of PAO6 base oil to some extent, which is favourable for its application in lubrication engineering. [ABSTRACT FROM AUTHOR]

Intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections have emerged as the most common therapeutic approach for the management of diabetic macular edema (DME). Despite their proven superiority over other interventions, there is a paucity of data regarding the relative effectiveness of anti-VEGF agents in treating DME diagnosed with different patterns of optical coherence tomography (OCT). In this regard, we conducted a systematic review and comparative analysis of the therapeutic efficacy of intravitreal bevacizumab, ranibizumab, aflibercept, and conbercept in the management of DME with diffuse retinal thickening (DRT), cystoid macular edema (CME), and serous retinal detachment (SRD) patterns identified using OCT. Our study encompassed a comprehensive search of PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and Wan Fang Data from their inception until January 25, 2023. The network meta-analysis involved the inclusion of 1606 patients from 20 retrospective studies with a moderate risk of bias but no evidence of publication bias. The DRT group had the highest increase in best-corrected visual acuity (BCVA) with anti-VEGF, while the SRD group had the greatest reduction in Central Macular Thickness (CMT). Furthermore, conbercept, ranibizumab, and bevacizumab, respectively, showed the best treatment outcomes for patients with DRT, CME, and SRD in terms of improvement in BCVA. And, conbercept exhibited the highest reduction in CMT in the DRT, CME, and SRD groups. In conclusion, our study highlights the efficacy of anti-VEGF agents in the management of DME and provides valuable insights into the selection of anti-VEGF agents tailored to the individual needs of patients. [ABSTRACT FROM AUTHOR]

This work demonstrates high-performance AlN/GaN double-barrier resonant tunneling diodes (RTDs) with high peak current density grown by plasma-assisted molecular beam epitaxy on c-plane free-standing GaN substrates, featuring stable and repeatable negative differential resistance (NDR) characteristics at room temperature. By scaling down the barrier thickness of AlN barrier and the lateral mesa size of collector, the record peak current density of 1551 kA/cm2 is achieved along with a peak-to-valley current ratio (PVCR) of 1.24, which is attributed to the reduced resonant tunneling time under thinner AlN barrier and the suppressed external incoherent valley current by reducing the dislocation number contained in the RTD device with the smaller size of collector. By statistically analyzing the NDR performance of RTD devices with different thicknesses of AlN barrier, the average peak current density increases from 145.7 to 1215.1 kA/cm2, while the average PVCR decreases from 1.45 to 1.1, correspondingly, accompanying with a decreased peak voltage from 6.89 to 5.49 V, with downscaling the AlN barrier thickness from 1.5 to 1.25 nm. The peak current density obtained in this work is the highest value among all the reported nitride-based RTDs up until now while maintaining high PVCR value simultaneously, which illustrates that ultra-scaled RTD based on vertical quantum-well structure and lateral collector size is a valuable approach for the development of nitride-based RTDs with excellent NDR characteristics and reveals their great potential applications in high-frequency oscillation sources and high-speed switch circuits. [ABSTRACT FROM AUTHOR]

To explore the intervention effect of exoskeleton robot training on anxiety of stroke patients. Methods 24 stroke patients with hemiplegia were randomly divided into experimental group and control group, with 12 cases in each group. Moreover, the robot group took the walking training with UGO 210, a lower limb exoskeleton walking rehabilitation, once per day, 30 minutes per time, a total of 20 times of treatment. Before the trial and at the end of the trial cycle, patients’ emotions were assessed using the Self-rating Anxiety scale (SAS), and the efficacy of the two groups was compared. Results: The scores of anxiety scale decreased in both groups (P

Here, we present a systematical investigation of AlN/GaN double-barrier resonant tunneling diodes (RTDs) grown by plasma-assisted molecular beam epitaxy on metal-organic chemical vapor deposition GaN-on-sapphire templates. The processed devices featured an active region composed of 2.5 nm GaN quantum well sandwiched by two 1.5 nm AlN barriers and RTD mesa diameter ranging from 1 to 20 μm. Room temperature current–voltage characteristics exhibited a repeatable negative differential resistance (NDR) free of degradation and hysteresis after 1000 times subsequently up-to-down voltage sweeps across different sizes. High peak-to-valley current ratios of 1.93 and 1.58 were obtained at room temperature for 1 and 12 μm diameter devices, respectively, along with peak current densities of 48 and 36 kA/cm2 corresponding to peak voltages of 4.65 and 5.9 V. The peak current density decreased quickly initially and then was less susceptible to this averaging effect with increasing the device diameter. Temperature-dependent measurements revealed that the valley current density displayed a positive relationship to the temperature, and an abruptly increasement was observed for the devices with a diameter of 20 μm when the temperature rose over 230 K. We attributed this abnormal phenomenon to the increased contribution from acoustic and longitudinal optical (LO) phonon scattering, especially for the LO phonon scattering. The area dependence of electrical performance suggested that the leakage pathway through dislocations played a vital role for charge transport and there existed a threshold of dislocation density for NDR characteristics. These results promote further study for future implementation of III-nitride-based RTD oscillators into high-frequency and high-power terahertz radiation. [ABSTRACT FROM AUTHOR]

Background: The epidemiological features of Guillain-Barré syndrome (GBS) were different in different areas; a comparison of the disease was needed to identify the variation and prognosis. We compare the epidemiological features of GBS in different areas in China. Method: A total of 1,191 patients were included. Information was collected in patients diagnosed with GBS and its variants in middle and south China, and then retrospectively reviewed. The patients were divided into four different regions: East China (n = 441), Center China (n = 566), South China (n = 77), and Southwest China (n = 107). These subregions are mainly divided by climate and geographical location. These data were compared with data from a study in East China (Shandong, n = 150) and Northeast China (Changchun, n = 750). Results: Patients from the south and southwest China were younger than other regions (P = 0.000). A summer peak and an autumn peak were found in northern China, but more patients in winter and spring days in other areas (P = 0.000). Upper respiratory tract infection (URTI) was the preceding event of GBS patients in all regions but rarer in central China (P = 0.001). The proportion of axonal subtype was higher in central and southwest China than in other regions (P = 0.001). Patients in southwest China were more served at nadir and have the longest hospital stay (P = 0.003 and P = 0.000). Conclusion: The difference between seasonal variation and preceding events was found in different regions in China; clinical features differ among regions in China. [ABSTRACT FROM AUTHOR]

In this Letter, we present the excellent negative differential resistance (NDR) characteristics of AlN/GaN double-barrier resonant tunneling diodes (RTDs) in which the active layers are grown by molecular beam epitaxy on thick GaN-on-sapphire templates manufactured by metal-organic chemical vapor deposition. Here, indium flux is introduced as surfactant to reduce the interface roughness and improve the sharpness of heterointerface during epitaxial growth of AlN/GaN/AlN quantum well. The processed device with a top collector diameter of 1 μm size demonstrates a record peak current density of 1039 kA/cm2 while simultaneously featuring a peak-to-valley current ratio of 1.23 at room temperature, excellent achievements among all the reported GaN-based RTDs on any substrates. In addition, no degradation of device performance together with free of hysteresis is observed for the 1000 times consecutive up-to-down voltage sweeps under forward bias. These remarkable achievements are attributed to the marked improvement in heterointerface quality of AlN/GaN/AlN double-barrier quantum well by adopting indium as surfactant during epitaxial growth as clarified by transmission electron microscopy analysis, which dramatically suppresses the interface roughness scattering and elements interdiffusion, thus significantly improving the NDR signatures in current–voltage curves. The obtained results in this work illustrate that indium-surfactant added epitaxy technique turns out to be a promising approach for the modulation of vertical electron resonant tunneling in III-nitride heterostructures and realization of highly reproducible and reliable AlN/GaN double-barrier RTDs, in favor of implementation for future high-power solid-state electronics operating in terahertz spectra. [ABSTRACT FROM AUTHOR]

Objective: Acute bulbar palsy plus (ABPp) syndrome is a rare regional variant of Guillain-Barré syndrome (GBS) characterized by acute bulbar palsy combined with other cranial symptoms or ataxia without limb and neck weakness. We aim to investigate characteristics of ABPp syndrome and analyze its nosological position within the GBS spectrum. Methods: A patient with ABPp syndrome was reported, and previous case reports of patients who met the criteria for ABPp syndrome from the literature were reviewed. Results: A total of 28 patients were included in our study. Median age was 32 years. Most of the patients (78.6%) were from Asia, and 75.0% had preceding infection. The main accompanying symptoms were ophthalmoplegia (85.7%), facial palsy (60.7%), and ataxia (50.0%). There existed asymmetric weakness in the form of unilateral facial palsy (32.1%) and ptosis (3.6%). Approximately half of the patients had albuminocytological dissociation. All the tested patients were seropositive for antiganglioside antibodies, of which the two most common were immunoglobulin G (IgG) anti-GT1a (77.3%) and anti-GQ1b (59.1%) antibodies. Over one-third of the patients who underwent electrophysiological assessment showed subclinical neuropathy beyond cranial nerves. The outcome was generally favorable as 89.3% of patients made full recovery within 5 months. Conclusion: The hitherto largest case series of ABPp syndrome advances our understanding of this disease. Serologically, the presence of IgG anti-GT1a and anti-GQ1b antibodies predicts and contributes to the disease. Phenotypically, ABPp syndrome is more prone to be a separate subtype of GBS than overlap of distinct subtypes and has the potential to complement current diagnostic framework of GBS. [ABSTRACT FROM AUTHOR]

Background: Guillain-Barré syndrome (GBS), an autoimmune disease and an acute inflammation disorder, is currently the most frequent cause of acute flaccid paralysis worldwide. EAN, an animal model of GBS, is a CD4+ T cell-mediated autoimmune disease of the PNS. Wnt/β-catenin signals are critically important to several fundamental aspects of peripheral nerve development and play a crucial role in Schwann cell proliferation. Here, we investigate the role of Wnt/β-catenin signalling cascades in EAN rats. Methods: 28 male Lewis rats weighing 170 ± 10 g were randomly divided into control group (n = 7) and EAN groups (Early group; Peak group and Recovery group. n = 7 per group). EAN rats were immunized with P257-81 peptide; weighed daily, and the neurologic signs of EAN were evaluated every day. The sciatic nerve was taken on the days 10, 17, and 30 p.i. for H&E staining, transmission electron microscopy and immunohistochemical staining; blood samples were collected weekly from caudal vein to detect IFN-γ, IL-4, TGF-β1; and the sciatic nerve was taken to examinate the dynamics expression of Wnt/β-catenin pathway molecules. Results: In our study, we chose tail-root injection to better model GBS. Moreover, we observed that IFN-γ levels paralleled clinical EAN, and the levels of TGF-β1 and IL-4 gradually increased and peaked in the recovery phase. In addition, we have shown that canonical Wnt signalling is upregulated and reached a peak in the late recovery phase. Conclusion: Our findings suggest that Wnt/β-catenin signalling is associated with the promotion of remyelination in EAN rats. [ABSTRACT FROM AUTHOR]

Highlights: Using NiFe2O4 quantum dots (QDs) as additive substitutes, the total carbon content in cathodes is sharply reduced from original ~ 26% (in traditional S/C cathodes) to a low mass ratio of ~ 5%. The as-built S@CB ⊆ QDs demonstrate more appropriate tap density (~1.32 g cm−3) and specific surface area (~19.9 m2 g−1) values than S@CB counterparts. NiFe2O4 QDs additives possess superb chemisorption interactions with Li2Sn molecules and proper charge-transfer/catalytic features to strengthen redox kinetics of overall cathode systems.Smart combination of manifold carbonaceous materials with admirable functionalities (like full of pores/functional groups, high specific surface area) is still a mainstream/preferential way to address knotty issues of polysulfides dissolution/shuttling and poor electrical conductivity for S-based cathodes. However, extensive use of conductive carbon fillers in cell designs/technology would induce electrolytic overconsumption and thereby shelve high-energy-density promise of Li–S cells. To cut down carbon usage, we propose the incorporation of multi-functionalized NiFe2O4 quantum dots (QDs) as affordable additive substitutes. The total carbon content can be greatly curtailed from 26% (in traditional S/C cathodes) to a low/commercial mass ratio (~ 5%). Particularly, note that NiFe2O4 QDs additives own superb chemisorption interactions with soluble Li2Sn molecules and proper catalytic features facilitating polysulfide phase conversions and can also strengthen charge-transfer capability/redox kinetics of overall cathode systems. Benefiting from these intrinsic properties, such hybrid cathodes demonstrate prominent rate behaviors (decent capacity retention with ~ 526 mAh g−1 even at 5 A g−1) and stable cyclic performance in LiNO3-free electrolytes (only ~ 0.08% capacity decay per cycle in 500 cycles at 0.2 A g−1). This work may arouse tremendous research interest in seeking other alternative QDs and offer an economical/more applicable methodology to construct low-carbon-content electrodes for practical usage. [ABSTRACT FROM AUTHOR]

Objective: To determine whether virtual reality (VR)-based dynamic standing balance training improves three elements of sensory integration and investigate whether VR-based dynamic standing balance training results in improved outcomes, especially regarding balance and gait, compared to the standard training method., Design: This single-blinded, randomized, controlled trial involved 30 patients with hemiplegia. The experimental (EG, n = 15) and control (CG, n = 15) groups received VR augmented-standing balance training or standard standing balance training, respectively, for 20 minutes, 5 days a week, for 3 weeks. The patients were assessed for primary (Sensory Organization Test [SOT] and the Berg balance scale [BBS]) and secondary (the functional reaching test and timed up-and-go test [TUG]) outcomes before and after training., Results: From preintervention to postintervention, the BBS score (F = 26.295, p < 0.05), TUG score (F = 18.12, p < 0.05), mean score of conditions 2 (F = 4.36, p < 0.05) and 6 (F = 5.61, p < 0.05), and composite score of the SOT (F = 5.385, p < 0.05) in both groups were significantly improved. However, there was no significant difference between EG and CG (time*group p > 0.05)., Conclusion: VR combined with standing balance training improved sensory integration, postural control, balance, and gait ability in patients with hemiplegia, reducing fall risk. However, outcomes were comparable to general balance training regarding balance and gait., Competing Interests: Conflict of interest Statement: There is no conflict of interest to declare., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Purpose: We aimed to determine the clinical features of Miller Fisher syndrome (MFS) in southern China and compare them with those presenting in other countries., Methods: We collected the medical records of patients diagnosed with MFS during 2013-2016. We analyzed the age, sex, onset season, precursor events, clinical symptoms and signs, findings of nerve conduction studies (NCS), cerebrospinal fluid (CSF), therapeutic remedies, nadir time, and length of hospital stay of patients with MFS in southern China. We concurrently compared the differences between urban and rural areas and between patients with incomplete ophthalmoplegia (IO) and complete ophthalmoplegia (CO)., Results: The study enrolled 72 patients: 36 from rural areas and 36 from urban areas, and 50 males and 22 females. The mean age at onset was 47.72 years, and 30 (41.7%) and 21 (29.2%) patients developed MFS in spring and winter, respectively. The typical triad of ophthalmoplegia, ataxia, and areflexia was observed in 50 (69.4%) patients. A history of upper respiratory tract infection 1 week before onset was found in 52.8% of the patients, while 5.6% experienced gastrointestinal infections and 48 (73.8%) exhibited albuminocytological dissociation in the CSF study. Only 26 (36.1%) patients presented abnormalities in NCS. Moreover, restricted outward eyeball movement presented in 83.5% of the patients with classic MFS and acute ophthalmoplegia, and bilateral symmetrical ophthalmoplegia presented in 64.2%. With the exception of the higher proportion of NCS abnormalities in urban areas (47.2% vs. 25.0%), urban and rural differences were insignificant regarding sex ratio, age at onset, high-incidence season, precursor events, disease characteristics, and albuminocytological dissociation in the CSF. Furthermore, patients with CO were older than those with IO (64.53±7.69 vs. 43.19±14.40 years [mean±standard deviation], p <0.001)., Conclusions: The patients with MFS were mostly male and middle-aged, and most presented in winter and (especially) spring. More than half of the patients had clear precursor events, most of which were classic MFS with the typical triad. More than 70% of the patients presented albuminocytological dissociation in the CSF. NCS abnormalities were uncommon in MFS. The age at onset was lower in patients with IO than in patients with CO; bilateral symmetrical extraocular muscle paralysis was the most common symptom, and the external rectus was the most frequently involved muscle., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2023 Korean Neurological Association.)

Objectives: To evaluate the application value of CT-based radiomics features for the ascending and descending types of nasopharyngeal carcinoma (NPC)., Methods: A total of 217 NPC patients (48 ascending type and 169 descending type), who obtained CT images before radiotherapy in Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University from February 2015 to October 2017, were analyzed retrospectively. All patients were randomly divided into a training set ( n =153) and a test set ( n =64). Gross tumor volume in the nasopharynx (GTVnx) was selected as regions of interest (ROI) and was analyzed by radiomics. A total of 1 300 radiomics features were extracted via IBEX. The least absolute shrinkage and selection operator (LASSO) logistic regression was performed to choose the significant features. Support vector machine (SVM) and random forest (RF) classifiers were built and verified., Results: Six features were selected by the LASSO from 1 300 radiomics features. Compared with SVM classifier, RF classifier showed better classification performance. The area under curve (AUC) of the receiver operating characteristic (ROC) curve, accuracy, sensitivity, and specificity were 0.989, 0.941, 1.000, and 0.924, respectively for the training set; 0.994, 0.937, 1.000, and 0.924, respectively for the validation set., Conclusions: CT-based radiomics features possess great potential in differentiating ascending and descending NPC. It provides a certain basis for accurate medical treatment of NPC, and may affect the treatment strategy of NPC in the future.

Pyrite FeS 2 has long been a research focus as the alternative anode of rechargeable Ni-Fe cells owing to its eye-catching merits of great earth-abundance, attractive electrical conductivity, and output capacity. However, its further progress is impeded by unsatisfactory cyclic behaviors due to still "ill-defined" phase changes. To gain insights into the pyrite working principles/failure factors, we herein design a core-shell hybrid of a FeS 2 @carbon nanoreactor, an optimal anode configuration approaching the practical usage state. The resultant electrodes exhibit a Max . specific capacity of ∼272.89 mAh g -1 (at ∼0.81 A g -1 ), remarkably improved cyclic longevity/stability (beyond ∼80% capacity retention after 10 3 cycles) and superior rate capability (∼146.18 mAh g -1 is remained at ∼20.01 A g -1 ) in contrast to bare FeS 2 counterparts. The as-built Ni-Fe full cells can also output impressive specific energy/power densities of ∼87.38 Wh kg -1 / ∼ 11.54 kW kg -1 . Moreover, a refreshed redox reaction working mechanism of "FeS 2 OH ↔FeS 2 ↔Fe 0 (in pyrite domains) " is redefined based on real-time electrode characterizations at distinct operation stages. In a total cyclic period, the configured pyrite-based anodes would stepwise undergo three critical stages nominally named "retention", "phase transition/coexistence", and "degradation", each of which is closely related to variations on anodic compositions/structures. Combined with optimal electrode configurations and in-depth clarifications on inherent phase conversions, this focus study may guide us to maximize the utilization efficiency of pyrite for all other aqueous electrochemical devices.

Objectives: The clinical and epidemiological profiles of Guillain-Barré syndrome (GBS) in southern China have yet to be fully recognised. We aimed to investigate the subtypes of GBS in southern China, compare the clinical features of demyelinating form with that of axonal form and test whether preceding infections and age have influence on the clinical phenotype, disease course and severity of GBS., Methods: Medical records of patients with a diagnosis of GBS admitted to 31 tertiary hospitals, located in 14 provinces in southern China, from 1 January 2013 to 30 September 2016, were collected and retrospectively reviewed., Results: Finally. 1056 patients, including 887 classic GBS and 169 variants, were enrolled. The 661 classic patients with available electromyographic data were grouped as having acute inflammatory demyelinating polyneuropathy (AIDP, 49.0%), acute motor axonal neuropathy (AMAN, 18.8%), inexcitable (0.9%) and equivocal (31.3%). In contrast to AIDP, patients with AMAN were characterised by earlier nadir (P=0.000), higher Hughes score at nadir (P=0.003) and at discharge (P=0.000). Preceding upper respiratory infections were identified in 369 (34.9%) patients, who were more inclined to develop AIDP (P = 0.000) and Miller-Fisher syndrome (P = 0.027), whereas gastrointestinal infection were found in 89 (8.4%) patients, who were more prone to develop AMAN (P=0.000), with more severe illness (P=0.001) and longer hospital stay (P=0.009). Children (≤15 years) and the elderly (≥56 years) were more severe at nadir, the elderly had the longest hospital stay (P=0.023)., Conclusion: AIDP is the predominant form in southern China, which is different from data of northern China. The different subtypes, preceding infection and age of onset can partially determine the disease progression, severity and short-term recovery speed of GBS., Clinical Trial Registration: ChiCTR-RRC-17014152., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)